Patent Document 1 discloses a piezoelectric micro blower that sends air toward a cooling target object such as a CPU so as to cool the cooling target object.
FIG. 12 includes cross-sectional views illustrating a main part of the piezoelectric micro blower in Patent Document 1. FIG. 12(a) illustrates an initial state of the piezoelectric micro blower (when voltage is not applied thereto). FIGS. 12(b) to 12(e) illustrate blower operations of the piezoelectric micro blower when a diaphragm 2 as illustrated in FIG. 12(a) is bent and deformed in a primary resonance mode. Arrows in FIGS. 12(b) to 12(e) indicate flow of the air.
As illustrated in FIG. 12(a), the piezoelectric micro blower includes a blower main body 1, the diaphragm 2, and a piezoelectric element 3. The outer circumferential portion of the diaphragm 2 is fixed to the blower main body 1. The piezoelectric element 3 is bonded to a center portion of the rear surface of the diaphragm 2. A blower chamber 4 is formed between a first wall portion 1a of the blower main body 1 and the diaphragm 2. A first opening 5a communicating with the blower chamber 4 is formed on a region of the first wall portion 1a, which opposes the center portion of the diaphragm 2.
A second wall portion 1b is provided on the blower main body 1 so as to be spaced from the first wall portion 1a. A second opening 5b communicating with the blower chamber 4 is formed on a region of the second wall portion 1b, which opposes the first opening 5a. An inlet passage 7 communicating with the first opening 5a and the second opening 5b is formed between the first wall portion 1a and the second wall portion 1b. 
In the above-mentioned configuration, when a driving voltage is applied to the piezoelectric element 3, as illustrated in FIGS. 12(b) to 12(e), the diaphragm 2 is bent and deformed with expansion and contraction of the piezoelectric element 3, so that a volume of the blower chamber 4 changes periodically.
First, as illustrated in FIG. 12(b), when the driving voltage is applied to the piezoelectric element 3 and the diaphragm 2 is bent to the piezoelectric element 3 side, the volume of the blower chamber 4 is increased. Accompanied with this, a part of the air in the inlet passage 7 is sucked into the blower chamber 4 through the first opening 5a. 
Then, as illustrated in FIGS. 12(c) and 12(d), when the driving voltage is applied to the piezoelectric element 3 and the diaphragm 2 is bent to the blower chamber 4 side, the volume of the blower chamber 4 is decreased. Accompanied with this, the air in the blower chamber 4 is discharged through the second opening 5b via the first opening 5a. 
In this case, the airflow that is discharged from the blower chamber 4 discharges air present at the outside of the blower main body 1 through the second opening 5b while sucking the air via the inlet passage 7. Thereafter, the diaphragm 2 is returned to the state as illustrated in FIG. 12(b) after having experienced the state as illustrated in FIG. 12(e).
The piezoelectric micro blower in Patent Document 1 cools the cooling target object such as the CPU by directing the second opening 5b to the cooling target object so as to discharge the air sucked from the outside of the blower main body 1 toward the cooling target object.
Patent Document 1: International Publication No. 2008/069266
In the piezoelectric micro blower in Patent Document 1, the temperature of the air that is discharged onto the cooling target object is the same as the temperature (hereinafter, referred to as “environment temperature”) of the air at the outside of the blower main body 1. Therefore, the piezoelectric micro blower in Patent Document 1 cannot cool the cooling target object to a temperature lower than the environment temperature.
Further, the piezoelectric micro blower in Patent Document 1 is reduced in size, so that a flow rate of the air that can be sucked from the outside of the blower main body 1 is low. Due to this, a discharge flow rate is low and it takes a long time to cool the cooling target object.
Accordingly, the piezoelectric micro blower in Patent Document 1 has a problem that it cannot cool the cooling target object to a temperature equal to or lower than the environment temperature quickly.